Heavy Carbene Analogues: Donor‐Free Bismuthenium and Stibenium Ions

Abstract

Kinetically stabilized congeners of carbenes, R₂ C, possessing six valence electrons (four bonding electrons and two non-bonding electrons) have been restricted to Group 14 elements, R₂ E (E=Si, Ge, Sn, Pb; R=alkyl or aryl) whereas isoelectronic Group 15 cations, divalent species of type [R₂ E]⁺ (E=P, As, Sb, Bi; R=alkyl or aryl), were unknown. Herein, we report the first two examples, namely the bismuthenium ion [(2,6-Mes₂ C₆ H₃ )₂ Bi][BAr^F₄ ] (1; Mes=2,4,6-Me₃ C₆ H₂ , Ar^F =3,5-(CF₃ )₂ C₆ H₃ ) and the stibenium ion [(2,6-Mes₂ C₆ H₃ )₂ Sb][B(C₆ F₅ )₄ ] (2), which were obtained by using a combination of bulky meta-terphenyl substituents and weakly coordinating anions.